Levobetaxolol hydrochloride ((S)-Betaxolol hydrochloride) is a beta-adrenergic receptor inhibitor (beta blocker), used to lower the pressure in the eye in treating conditions such as glaucoma.

β2-adrenoceptor:32.6 nM(Ki), β1-adrenoceptor:0.76 nM(Ki)

Levobetaxolol potently antagonizes functional activities at cloned human β1 and β2 receptors, and also at guinea pig atrial β1, tracheal β2 and rat colonic β3 receptors with IC50s of 33.2 nM, 2970 nM and 709 nM, respectively. Levobetaxolol (Ki = 16.4 nM) is more potent than dextrobetaxolol (Ki = 2.97 μM) at inhibiting isoproterenol-induced cAMP production in human non-pigmented ciliary epithelial cells. [1] Levobetaxolol (topically applied) has been shown to reach the back of the eye in sufficient quantities to protect retinal ganglion cells from various types of insults. Levobetaxolol displaces [3H]-nitrendipine for L-type voltage-dependent calcium channel receptor with IC50 of 29.5 μM in rat cortex. Levobetaxolol reduces NMDA-stimulated 45Ca2+ influx by 47.3%. Levobetaxolol (topically applied) reduces the b-wave amplitude caused by ischaemia/reperfusion. [2]

Levobetaxolol (150 mg/eye) is more potent than dextrobetaxolol, reducing intraocular pressure by 25.9% in conscious ocular hypertensive cynomolgus monkeys. [1] Levobetaxolol (20 mg/kg) significant protects retinal function and results in significantly thicker the RPE and outer nuclear layer in a photic-induced retinopathy rat model. Levobetaxolol (20 mg/kg) results in a 10-fold up-regulation of bFGF and a two-fold up-regulation of CNTF mRNA levels, trophic factors that have been shown to inhibit retinal degeneration in a number of species. [3]